TNF and amyotrophic lateral sclerosis: For instance, a comparison between ALS patients and healthy subjects showed increased secretion levels of interleukin (IL)-6, interferon (IFN)-γ, and TNF-α in peripheral blood mononuclear cells (PBMC) after stimulation with antigenic peptides derived from HERV-K envelope (env) glycoproteins [73] (Figure 2).